Adjacent track erasure (ATE), sometimes called adjacent track encroachment, is an issue faced by magnetic data storage systems because of high tracks per inch (TPI) drive integration. Since the areal density of hard disk drives has been increasing by about 60-100% annually in recent years, the track density measured by TPI has increased substantially.
ATE occurs when track(s) adjacent to a track of interest (also referred to as a center track) are written to multiple times. As a result, the center track signal (on-track condition) will be contaminated with white noise. Also, the average amplitude of the center track may drop due to being partially erased. The signal amplitude drop and/or noise enhancement of the center track signal leads to significant signal to noise ratio (SNR) degradation, which translates to a drop in bit error rate (BER).
FIG. 1A is a diagram showing an example of a magnetic disk. In that example, disk 150 includes center track 154 and adjacent tracks 152a and 152b. In that example, writing to adjacent tracks 152a and/or 152b affects the information stored in center track 154 even if center track 154 is not intentionally or directly written to. It would be desirable to develop techniques that address the affects of ATE.